Granular silica

The essential attributes of the ideal material for use as a separator in VRLA cells are now well understood. A wide range of materials and material combinations has been evaluated for this purpose, and it has emerged that materials with small pore size (high surface area) and very little compressibility show good prospects for extending the cycle-life of VRLA batteries. 

It remains to be seen which of the many separator materials will be successful in commercial applications. Obviously, this will depend on costs and market requirements, as well as on performance. Although most of the developments reviewed here have been directed towards EV batteries, many of the findings are equally applicable to valve-regulated lead-acid batteries intended for use in other applications. 

Culpin, J.A. Haymati, in LJ. Pearce (Ed.), Power Sources 11. Research and Development in Nonmechanical Electrical Power Sources, International Power Sources Symposium Committee, Leatherhead, England, 1986, pp. 45-66. 

Berndt, Maintenance-Free Batteries, Research Studies Press Ltd., Taunton, England, 1997, p. 152. 

Bohnstedt, in J.O. Besenhard (Ed.), Handbook of Battery Materials, Wiley VCH Weinheim, 

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Occasionally, granular silica (supplied either by the Ottawa Silica Co. or Fisher Scientific Co.) was added to the plutonium solution for various periods before centrifugation to determine its effect on the colloidal system. The silica was first dry sieved, washed thoroughly, then oven dried at 120 °C. the particle sizes ranged from 280 to 390p. Other chemicals used were reagent grade. 

To determine if bicarbonate has similar effects on the nature of the radiocolloid, the plutonium size distributions were studied at pH 7 as a function of bicarbonate concentration, using bicarbonate only from atmospheric CO.j and in solutions with [CH(V] equal to 10"2Af. The latter were prepared by adding NaHCOa. Two different ionic strengths were used to distinguish between the effects of added bicarbonate and ionic strength. The distributions of identical solutions which were shaken in flasks with and without granular silica were determined initially and... 

Granular silica (crystalline quartz) and transparent silica plates (1 X 3 inches) were used for the sorption studies. The granular silica was supplied by the Ottawa Silica Co. and the Fisher Scientific Co. The silica was sized by dry-sieving with U. S. Standard sieves. In most cases, as narrow a range as possible was chosen, and the mean diameters, except where size was a variable, ranged from 275 to 387 microns. The transparent silica plates were fused silica with a smooth amorphous surface. 

Figure 2. Sorption of 10 7M plutonium at pH 7 on granular silica as a function of solution age prior to sorption...

Figure 3. Sorption isotherms on granular silica for fresh and aged (7 days) plutonium solutions at pH 7 and 0.1 M ionic strength...

Figure 6. Effect of pH on the rate of desorption of plutonium from granular silica into an infinite solution at an ionic strength...

Granular silica. In the early 1990s, Japan Storage Battery developed a VRLA battery in which the add was immobilized by closely packed granular silica that was filled between and around the plates [51 53]. The silica consists of fine primary particles and of coarser secondary particles formed by agglomerates of the primary particles. While the fine primary particles immobilize the add, the interstices... 

The wax patterns are cleaned with water or organic solvent and coated with a wetting agent, which helps the ceramic slurry to adhere to the wax. The cluster is then dipped in a liquid ceramic slurry, stuccoed with granular silica, zircon or alumina/silica refractories and then dried before the application of the next coat. The coating process is continued until a sufficiently thick shell is established. 

One of the most promising options of flexible insulation materials to be used for translucent foil structures involves granular silica aerogel as insulation material - see Fig. 12.2 (Cremers, 2008). Not only does aerogel have excellent thermal-insulation properties (see r-values and /-values in Fig. 12.3), but it is translucent as well. 

Granular Silica Aerogel (Nanogel ) by Cabot Corp. 

Broecker FJ, Heckmann W, Fischer F, Mielke M, Schroeder J, Stange A (1986) Stmctural analysis of granular silica aerogel. Springer Proc Phys 6 160-166... 

Broecker F J, Heckmann W, Fischer F et al (1985) Structural Analysis of Granular Silica Aerogels. In Fricke J (ed) International Symposium on Aerogels 6, Springer, Heidelberg... 

Figure 26.10. Granular silica ambigels in a beaker and individual granules (top and bottom photographs respectively) obtained by evaporative drying at moderate temperature of silica gels synthesized via a two-step acid/base catalyzed process [35], with courtesy of Rigacci A. and Achard P.

Qin, G., Y. Yao, W. Wei, and T. Zhang. 2013. Preparation of hydrophobic granular silica ataogels and adsorption of phenol from water. Applied Surface Science 280 806-811. 

Silicones Molded, Laminated Eibrous (glass) reinforced silicones Granular (silica) reinforced silicones Woven glass fabric/ silicone laminate 0.18 0.25—0.5 0.075—0.125... 

Silicones Molded, Laminated Granular (Silica) Reinforced 2.5—5.0x10 ... 

Silicone Granular (silica) reinforced 4—6 (ASTM D651)... 

Silicone, Molded Granular (silica) reinforced silicones 10.6—17... 

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